Device for making coffee-cream for espresso coffee-machines

ABSTRACT

A device for application to moka espresso coffee machines, for producing coffee-cream comprises, downstream of a filter ( 5 ) overlaying a coffee powder holding basket ( 2 ), a membrane ( 7 ) made of rubber or other elastomeric material including one or more holes ( 8 ) having a very small diameter and/or one or more incisions, thereby causing a pressure increase in water passing through the coffee powder, in addition to an increase of the speed of the coffee infusion passing through the holes of the membrane.

BACKGROUND OF THE INVENTION

The present invention relates to a device to be applied for espressocoffee machines, of the home type, which are conventionally called“moka” machines, for producing the “coffee-cream”.

As is known, to make the so-called “coffee-cream”, i.e. a foamedrelatively dense coffee infusion, by using coffee machines for home useis a rather difficult operation.

In fact, for making such a coffee type, it is necessary to supply theinfusion water through the powder coffee held in a powder coffee holderbasket, with such a pressure and speed as to allow the aromatic parts ofthe coffee powder to be easily extracted.

For achieving the above mentioned result in moka machines, devices havebeen already designed, but, said devices, have been found to be verycomplex and, which is most important, they cannot be applied on existingespresso coffee machines but require the construction of speciallydesigned coffee machines.

SUMMARY OF THE INVENTION

Accordingly, the main object of the present invention is to provide sucha constructively simple and unexpensive device which can be easilyapplied also to existing moka coffee machines, and which allows toproduce, by said machines, the so-called “coffee-cream”.

According to the main feature of the present invention, such devicecomprises a membrane made of a rubber or other elastomeric material,arranged downstream of the filter overlaying the coffee powder holdingrecess, said membrane comprising one or more holes of very smalldiameter, and/or one or more incisions, so as to provide an increase ofthe pressure eof water passing through the coffee powder, in addition toan increasing of the water speed during said passage, this result beingachieved since the heated water must pass through a narrowed passingport.

In particular, said incisions made through said resilient rubber orother elastomeric material membrane can have a rectilinear segmentconfiguration, or they can define a curved pattern, or a mixed pattern,i.e. comprising both rectilinear and curved portions.

Advantageously, said membrane is so constructed as to be rigid with thesealing gasket arranged between the boiler and coffee maker in saidmachines.

BRIEF DESCRIPTION OF THE DRAWING

Further objects, characteristics and advantages of the present inventionwill become more apparent hereinafter from the following detaileddisclosure of a preferred embodiment thereof, with reference to theaccompanying drawing, where:

FIG. 1 is a longitudinal cross-sectional view of a moka type of espressocoffee making machines, to which a device according to the presentinvention has been applied.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The coffee machines shown in the above mentioned figure, is of aconventional type and comprises, in per se known manner, a boiler 1, inwhich is arranged a fun-like element bearing the coffee powder basketelement 2.

On the boiler 1 a top cup element 3 is screwed, said top cup elementincluding a central upright tubular stem 4.

In prior coffee making machines, in the bottom of the coffee maker 3 topcup is arranged a perforated filter 5, and between said filter 5 andboiler 1 a sealing gasket 6 is provided.

According to the present invention, downstream of the perforated filter5 resilient membrane 7, including one or more microholes 8, having adiameter of few millimeter tens, for example 0.4 millimeters, isarranged.

The above mentioned microholes can also be replaced by small incisionsor notches, having a size varying from few tens of millimeters to fewmillimeters, and which are formed through the mentioned membrane 7.

Said membrane is preferably made of an elastomeric material, havingcharacteristics similar to that of rubber and, for example, can be madeby using silicone rubber.

Advantageously, the membrane 7 can be formed so as to form a singlepiece with the gasket 6.

In this case, the gasket 6 comprises a circular notch, formed along theperipheral inner edge thereof, and operating as a housing recess for theperipheral edge of the filter 5, as is clearly shown in FIG. 1.

The above disclosed device should be apparent from the above disclosure.

Actually, in delivering the coffee infusion, as the infusion pressuredownstream of the membrane 7 achieves a given value, the central regionof the membrane 7 is resiliently deformed, so as to be upward deflected.

The above mentioned deformation causes the mentioned holes 8 to beenlarged, thereby allowing the infusion to quickly pass through thecentral upright duct 4 into the coffee maker proper 3, while forming thedesired “coffee-cream”.

It should be apparent that the invention, as disclosed, is not limitedto the shown and disclosed embodiment, but is susceptible to severalvariations and modifications coming within the scope of the inventionand substantially as claimed in the accompanying claims.

1. A device, for application to moka coffee machines, for making theso-called “coffee-cream”, comprising a boiler (1) and a top cup (3), aperforated filter (5) in the bottom of said cup, whereby downstream ofsaid filter (5) overlaying a basket element (2) for holding a coffeepowder therein, is applied a membrane (7) made of rubber or otherelastomeric material and including one or more microholes (8), and/orone or more incisions, characterized in that said membrane (7) is rigidwith a sealing gasket (6) arranged between the coffee machine boiler (1)and cup (3), said sealing gasket (6) including an annular incisionextending along its inner peripheral edge for engaging therein an outerperipheral edge of said filter (5).
 2. A device, according to claim 1,characterized in that the microholes formed through said rubber or otherelastomeric material membrane have a size from 0.1 to 0.7 mm.
 3. Adevice, according to one or more of the preceding claims, characterizedin that said membrane is adapted to be deformed by the pressure appliedthereon by heated water, which heated water subjects said membrane to aresilient deformation to cause said membrane to assume a bulgedconfiguration, with an upward facing convexity, whereas the water andsteam exiting from the coffee machine boiler passes with a high speedthrough the coffee powder arranged in said coffee powder basket elementand said filter.
 4. A device, according to one or more of the precedingclaims, characterized in that said membrane is subjected to a pressurestress, because of its elasticity, and is so deformed as to cause saidmicroholes and/or slits therefrom to be enlarged thereby allowing acoffee and steam infusion flow to pass with a high speed therethrough.5. A device, according to one or more of the preceding claims,characterized in that said incisions have either a rectilinear or acurved configuration, or a configuration resulting from a combination ofdifferently shaped portions thereof.
 6. A device for application toespresso coffee machines, according to one or more of the precedingclaims, characterized in that said membrane (7) is separated from saidfilter.
 7. A device, according to one or more of the preceding claims,characterized in that said membrane (7) operates as a resilient safetyvalve, designed for allowing a quick passage of the coffee infusiontherethrough as in said boiler a pressure corresponding to an optimumtemperature for making a coffee-cream is achieved.
 8. A device,according to one or more of the preceding claims, characterized in thatsaid resilient membrane, upon ending the coffee infusion flow,automatically assumes its starting arrangement, so as to close saidmicroholes.